Haw. Rev. Stat. § 468M-5: Legal rate; computation.

Except as otherwise permitted by existing written contract, any activity desk that directly or indirectly receives any interest on the payment due to the activity provider, shall remit the interest and the payment due to the activity provider; provided that if the interest and payment due are not remitted within thirty days from the date of invoice, interest on the unpaid balance of the interest and payment due shall accrue at the rate of one per cent per month from the due date.